This invention relates to improvements in silo unloaders and, more particularly, to improvements in the construction and function of their discharge spout assembly comprised of a discharge spout and the underlying torque arm on which the outer end of the spout is based. Preferred embodiments feature control means connected to the torque arm conditioned to interrupt the operation of the auger motor should stress be placed on the torque arm by reason of the fact the auger driven by the motor encounters an obstruction or is choked by the silage on which it operates. The improvements are such to not only facilitate the unloading of a silo but also to substantially reduce the stress and wear on unloader parts and the amount of maintenance which is normally required in respect thereto.
By way of illustration the invention improvements will be particularly described in application to a conventional unloader of the type which includes a tripod-like structure designed to mount in bridging relation to the upper end of a silo and to suspend, by cables, a tracking ring. In such an unloader, the auger unit is connected in underlying relation to the ring and supported by said ring with the intent that it should rotate about a vertical axis. To this end the auger unit mounts in connection therewith a plurality of rollers which are circularly spaced and designed to contact and bear on the inner surface of a silo wall as the auger moves over an underlying bed of silage. The rollers in their composite are intended to assist the auger to maintain a relatively uniform level of travel during a circular movement thereof, in the course of which the auger will pick up and move silage to a connected blower. The blower functions to discharge the silage in a pressured flow by way of an overlying spout. As mounted, the discharge spout extends upward and outward from a point central to the tracking ring. An underlying torque arm having a pivoted connection with the tracking ring supports on the outer projected end thereof a bracket for mounting the discharge end of the spout in overlying spaced relation thereto. The outer end of the torque arm hooks over the frame of a silo discharge opening to fix the position of the spout and direct its discharge through the opening. At the same time it limits rotation of the spout with the underlying auger. By reason of the fact that the spout assembly, comprised of the discharge spout and its underlying torque arm, must be manually moved from one silo discharge opening to another as the level of the silage diminishes during the unloading of the silo, the torque arm which underlies the discharge spout normally has a telescoping character.
Long experience has indicated that almost every silo is out of round. This very fact has produced much damage in use of silo unloaders and dictated the need for considerable maintenance and replacement of parts during the course of their operation, particularly in relation to the discharge spout and the underlying torque arm. Such problems have stemmed from the fact that as an auger tracks over a silage bed it will, be reason of its suspended mount and by reason of the fact that the wall surface upon which its projected rollers bear is out of round, be caused to constantly shift the vertical axis about which it operates to various inclined positions. This produces undesirable elements of force which are reflected to the torque arm and the outer end of the discharge spout. Since the auger unit is not only moving in a generally circular path but constantly lowering, these undesirable elements of force will tend to bend, twist and produce a binding of the telescoping parts of the torque arm, the natural consequence of which is to interfere with their function in their efforts to accommodate the lowering movement of the auger together with the associated parts of the unloader. The damage to the torque arm is compounded since, when it binds and does not properly function as the unloader constantly moves downward, its resistance to accommodating such movement is reflected to underlying structure, producing further unbalance in the auger function. Under such conditions, not only are wear, tear, and maintenance requirements increased in respect to the telescoping torque arm but also in respect to other parts of the unloader to which the problems produced in the function of the torque arm are reflected.
Further problems evidenced in use of prior art unloaders stem from the fact that as the unloader is moved downwardly within a silo during its function there are several points at which the discharge spout assembly must be adjusted to change the direction of its discharge from one window to a next lower silo window or opening. In accordance with the practice, one must manually lift the whole spout assembly, including its underlying torque arm, from the window frame to which the torque arm is hooked, back it off and drop it until the torque arm is aligned with and adjusted so it can be hooked on to the frame of the next lower window or opening in the silo wall. If there has been binding and damage to a torque arm due to circumstances such as above described, there are real problems in adjusting the torque arm to accommodate this change.
Another serious problem in the use and maintenance of unloaders of the prior art is that by reason of its large size and the need for frequent handling thereof the discharge spout is made of very light gauge metal. Since the discharge spout is subjected to a considerable amount of friction and wear in use thereof it will quickly deteriorate and require replacement. The experts in the prior art have long felt that users of the silo unloaders had to live with this problem as the better alternative to making the discharge spout of heavier metal, thereby increasing greatly the manual effort required in the process of adjusting the spout assembly to such a degree as to make it very difficult, if not impossible, for one man to handle the spout. The seriousness of this problem should be well recognized since many times only one man is available to operate the silo unloader and in many instances the silo structure dictates that there is insufficient room for more than one man to manipulate the spout assembly in moving the same from one silo window to another. There is another very serious problem in the use of silo unloaders of the prior art. Depending upon the sophistication of the unloader device the winch employed to lower the tracking ring is either motorized or operated manually through the medium of a handle. In either case the winch might be energized for too long a period of time or operating too fast, in which event the structure will be lowered too deeply into the silage and the solids will choke up and obstruct the free movement of the auger. The natural result is to place too much load on the auger motor and, in particular, on the related drive mechanism through the medium of which the auger is driven in a circular path. In this last respect the clutch embodied in the ring drive may slip. This will require immediate attention to and adjustment of the clutch mechanism. If the clutch does not slip and there is a continued drive effort, the torque arm in engagement with the frame of the window through which the unloader spout is discharging will shift to engage the side of the frame. When this last occurs, there is applied to the torque arm a lateral strain which bends its component parts, again producing a condition requiring maintenance and/or replacement of parts. Similar difficulties occur when in the course of the unloader operation the silage handled is too wet. In such case the weight of the silage is such it may not discharge through the silo window but will fall short thereof and pile up under the window in the path of the rotating auger and its housing. Should the wet silage pile up sufficiently, when the auger turns in a circular path the housing of the auger will run up against the piled silage and there will occur difficulties such as just described when the auger is choked up by being buried in the silage.
It is to the solution of the foregoing problems that the present invention is directed.